1. Field of the Invention
The present invention relates to a position measuring device with an adjusting device for a sensing device of a graduation. The adjusting device serves the purpose to adjust the sensing device in a plane extending parallel to the plane of the graduation.
2. Description of the Related Art
In incremental position measuring devices in which the graduation is constructed as a periodic grid, the grid is photoelectrically sensed by a sensing device which also has a corresponding grid graduation. The grids of the graduation and of the sensing device are adjusted to each other in order to optimize the sensing signals. When the grids are arranged parallel to each other in two planes and the grids extend at a small angle relative to each other, such an adjustment is called a moire adjustment. Such an adjustment is described, for example, in German patent No. 10 40 268. The moire adjustment must be very precise and should be durable, but should not be very complicated.
It is, therefore, the primary object of the present invention to provide a position measuring device of the above-described type in which the sensing device can be exactly adjusted by means of an adjusting device in a plane extending parallel to the plane of the graduation and which does not significantly increase the manufacturing costs.